When this level begins, the first betrayal will commence. The Monitor that you've been loyally following turns on you. Right off the bat, you'll have to deal with a batch of Sentinels that have turned against you. You have a Plasma Gun and a Shotgun, and the Plasma Gun works best to take out the Sentinels. Use the large, glass barriers for cover, then dart out and blast them. Repeat until all of them are gone.

When all the Sentinels fall, move to the blast door ahead and activate the control panel to open it. In the corridor ahead, you will see several Sentinels take on some Covenant Grunts and Elite. Hang back and let them destroy each other. They will whittle each other down so there are only a couple Grunts and an Elite left. Polish them off with the Shotgun, then move forward to encounter another Jackal and an Elite. Once they're dead, open the blast door and continue down the path to yet another blast door.

There are two shields here. Open the blast door with the panel to the right, then quickly duck behind one of the shields. The main area of concern is to the right, where an Elite is lurking. Stay behind the shield and only dart out when you have a clear shot. Then move forward out into the cold. There is a tower ahead. Go to the top of it to find lots of ammo, a Sniper Rifle and a health pack. Grab the Sniper Rifle and return to the area below. There is a ledge under the one you're standing on that contains several Grunts and an Elite. You can clear it out, but why waste ammo? Instead, move to the far left of the tower and slide down the inclines here (there are three) until you get to a path containing a Rocket Launcher. Use the Sniper Rifle to clear out the Elite in the snowy plain below, then grab the Launcher and head down the ramp nearby.

Through an opening in the structure to the right, you'll see a distant Covenant tank shelling your area. Don't stand out in the open too long, or you'll taste the pain. Instead, give up a serving of Rocket Launcher yourself. Aim slightly below the tank for the best results. When you see it explode, move through the tunnel and truck to the nearby Banshee. Get inside and throttle up to the nav point above. It's on a high platform with a pair of Elite. Use the cannon to clear out the enemy before landing. Then touch down on the platform and go through the door nearby.

Once inside, follow the nav point to the glowing core and step inside (with full shields). Your shields will be depleted, but you'll trigger a chain reaction in the core, destroying the generator. Then hightail it out of there, through the passage you came in. You'll pass a bunch of Sentinels heading in. Just run past them, out to your waiting Banshee.

When you arrive outside, there will be a pair of Banshees on the platform. Take whichever one is less damaged down to the next nav point. Again, use the weapons on your Banshee to clear this snowy bridge before getting out of the vehicle to head through the door.

Through the next series of buildings (you'll recognize them as the diamond-doored structures you battled through in Assault on the Control Room), you'll be going against the arrows to find your way. Any time there is an arrow pointing the wrong direction, follow that path and you'll be doing the right thing.

This is another one of those circular hallways. If you want to avoid the prolonged fight, cut through the center room to get to the exit, which leads down at a slight incline. This in turn leads to a long, high-ceilinged hallway with a sunken portion off to the right. At the opposite end of the hall, you'll encounter an Elite and several Grunts and Jackals. Wipe them out and move straight ahead. Continue down the path until you hear some ambient music start. This signals the beginning of a big mess. In the coming hallways, you'll have to battle through tons of Flood and Covenant, most of which are also fighting with each other. Stay down in the safety of the room you're in and let the warring factions kill each other off. When it sounds like the killing has stopped above, move out of your tunnel and start moving left, killing whatever is in your path.

When you've cleared the tunnel of enemies, head back to the area just right of the tunnel you were waiting in. Here, you'll find a pair of health packs, a Shotgun and some Frag Grenades. Make sure you pick up the Assault Rifle off of the floor here, because there are some Infection Flood ahead. As with the last room, you can cut across the center chamber to make this area go quicker. Just make sure you don't get surrounded.

When you get to the diamond doors, go through and exit into the snow again. You're back on the double bridges from the Assault level. Move forward and fire a shot to start the action. The Flood to the left will begin leaping over. Let them cut each other up for awhile, then move forward and deal with the leftovers. On the bridge ahead, you'll meet an armored Elite carrying a laser sword. Take him down with the Shotgun or Rocket Launcher and proceed, picking your way through the baddies until you reach the opposite door.

Move through the diamond door and into the next hallway. You won't see anything on your radar right away, but as you move forward, a bunch of Flood will suddenly appear. Fall back into the tunnel and take on the Flood in a line. This will make your job easier than being surrounded. When you have dropped all of the Combat Flood, eat through the Infection type, then move around the circular hallway, blasting the unsuspecting Flood. As you open the next diamond door, you'll surprise a pair of Elite. Chuck a Plasma Grenade at them and fall back. They will start waging war with some Flood in the ensuing passage. Wait and let it die down, then move into the long cathedral hall and clean up the rest of the Flood. Watch out, though. The last Flood in the hallway carries a Rocket Launcher. Drop him before he can use it.

Move through the hall to another circle hallway. Drop the Combat and Carrier Flood here, then finish up with the Assault Rifle. Move around the passage to the right. Midway through, you will hear an explosion and several Flood will charge. Face them if you want, otherwise, just cruise to the exit, grabbing the health pack near the door.

Outside, another double bridge awaits. This one is a little tougher to navigate, because there are Carrier Flood everywhere and Banshees circling overhead. The concept is still the same, though. Clear the bridge and make it to the other side, the whole time watching the Flood threat to the left. A Rocket Launcher Flood awaits at the three-quarter point, and a slew of Infection Flood will greet you at the opposite door. But you can pretty much blast a path through it all with your Shotgun and make your way to the diamond door.

Once inside the next circular hallway, it's business as usual. Plenty of Flood to kill. Be aware that there are many Carrier types in this hallway. Make sure you have room between you before you blast. Make your way to the left until you reach a passage with a slight down incline. Follow the path to a lift and go down. Infection Flood will harass you during the descent, but don't waste ammo on them. Just move through two sets of green doors to arrive at a short hallway with barricades to the right and left. Blast the Combat Flood that meet you at the end of the passage, then move through the obstacle-strewn path (blasting Flood all the way, of course) until you reach another huge diamond door. Go through and follow the path to the snowy outside.

As you exit, you'll see a Ghost parked ahead. Run to it and get on before someone else does. Then head right, away from the resistance. You'll see a path that cuts down between towe buildings. If you need health, drive the Ghost down here and grab one of the health packs. When you emerge on the other side, stay on the Ghost and take a right, moving past the large Covenant tank in your path. Your goal is the cave opening behind it. Since the tank is slow, you'll have no problem blowing right by it.

Once you do, follow the tunnel out to an icy lake. Stay on the Ghost and move through the support columns here. Take out the Jackals on the ice and move around the corner. Here, you'll discover an overturned Warthog, tons of ammo and a health pack. Turn the Warthog over and drive up the twisting path. Nail any Grunts that get in your way. Soon, you'll reach an open field near a tower. To the left of the tower are a pair of Banshees. You'll need to get to one of them to get to the next nav point. If you want, you can stay on the ice here and plug the Elite in the distance with the mounted machine gun. Or, you can just charge ahead, hop out of the 'Hog and get into a Banshee. What you decide will depend a lot on the amount of health you have.

Once you're in a Banshee, curl up and around the central tower toward the nav point. There are two platforms here, and they'll both need to be cleaed before you can enter the next tower. Focus on the circular platform first. It's got a lot of laser turrets and an armored Elite to worry about. Pick them off with the Banshee's cannons, and keep an eye on your shields. If you get into the red, land near one of the other Banshees parked on this tower and trade ships. Make sure everything is cleared off, then focus on the other platform, the one near the nav point. There's a pesky Grunt with an energy cannon here, but he can be wasted with a well-placed cannon shot. Once the platform is clear, park the Banshee and move inside.

Note: It is absolutely imperative that this entire platform is clear before going inside. If you leave enemies out here, they will steal your ride and you won't be able to complete the mission.

Once you enter the building, you'll have to clear out a group of Flood in the center of the room. Then, a stream of Infection Flood will appear. Take them down, then go near the core, destroying the generator. Once you do, more Flood will appear. Since you shields are depleted, you'll have to book it or you'll be dead. Have your Shotgun handy and blast a path through them, working toward the exit. Once you step outside again, you'll see your ride. Get in it!

==
The Tunnels Below==

Pilot your Banshee toward the nav point. You'll have to enter the tunnel here. Stay in the Banshee and blast the troops below, but always keep moving forward. If your Banshee gets too dinged, get out and go it on foot. You'll have to watch out for Rocket Launcher fire from the Flood below as well. Make your way to the end of this bending tunnel until you reach a blast door, then hop out and open it. Scoot through the gap in the doors, leaving your Banshee behind.

In the next huge bay, you'll meet with some Flood resistance. As you move across the bridge, several Flood will charge. There are several small walls to duck behind to gain cover along the way, so use them. As you near the end of the bridge, a panoply of Flood will come at you. Use grenades to thin their numbers, and watch out for Rocket Launcher fire. When you have safely cleared the enemy, move to the other side of the bridge and pick up the health packs here. There is scattered ammo and other gear here as well.

When you've got what you need, open the blast doors and move through. Go through one more set of blast doors, then exit into another snowy plain.

As you emerge from the tunnel, you'll see another skirmish between Covenant and Flood. Move to the right side of this open field and head forward. You'll see a group of Flood standing around in the snow. Toss a grenade in their midst and watch them fly. Clean up the scraps, then move forward and clear a path ahead of you. Pay special attention to the laser turrets ahead. Nearby, you'll find a Ghost. Get in as soon as possible and make your way to the crease in the rock ahead and slightly to the left. Leave the rest of the Covenant and Flood there to battle it out for themselves.

Maneuver the Ghost down an icy path littered with stones until you see another battle raging. At the mouth of a cave to the left, you'll find tons of ammo, a Rocket Launcher and a couple of health packs. Only get out of your Ghost if you need these items. Otherwise, forge ahead, blasting through the battle until you reach a low ledge. Maneuver your Ghost up the ledge using the left side of the rock face. There is some nasty stuff in the prairie ahead, including several Covenant tanks and a buttload of Elite. Since you're still in the Ghost, you're mobile. You don't have to worry yourself with the major conflict going on here. Instead, just cruise to the right side of the canyon. Between the two tanks, you'll see a pair of parked Banshees. Clear out some of the rabble around them and go drive your Ghost into the area. Hop out when you get close, then quickly get into the drivers' seat of the Banshee. Then step on the gas and don't linger, because the tanks will make you pay for dallying.

Fly the Banshee up to the nav point platform. Try to knock the Sentinels that greet you out of the sky, then land and scoot into the diamond door. Near the entrance, you'll get some Frag Grenades and a health pack. Follow the path to another circular hallway, where you'll meet more nasty Sentinels. Smoke them, then move to the final generator core. The level has ended.